Hi everyone. OP here with an update. As I mentioned before, I decided to just go the nice route and inquire about the identical barrettes and I said I was a bit disappointed by the shipping issue.
The seller responded pretty quickly. (I did it from my computer to be safe!) She said that she had someone helping her getting her shipments together and they must have made a mistake with sending two if the same barrettes. (Said she has a little girl so she totally understands the issue.
So she just asked me to send her a picture of the barrettes on and she would send a correct one directly to the birthday girl. So yay!
Regarding the shipping, she said she had misunderstood our agreement and thought that she had got the order done quickly enough so it wouldn't be an issue and she was sorry about cutting it so close.
(I looked at our emails and in response to my discussing shipping it to my friend and she had responded that she thought she could get it to me in time so I figured since I hadn't pressed the issue - as some of you mentioned - it was partly on me. She had thought shipping would take 2-3 days when, in fact it took 5 so I think that was the problem.)
So since it seems like she is remedying the situation I will leave positive feedback. :-)